1. Field of the Invention
This invention relates to an apparatus and method for conductive heating and cooling of articles, and more particularly, relates to an apparatus and method employing electrical heating elements in conjunction with circulating cooling water to effect accurate heating and cooling of articles.
2. Description of Related Art
There are currently a number of items on the market which alternately employ electrical heating elements and circulating cooling water to heat up and then cool down a working surface on which articles to be thermally processed are mounted. Such apparatus provide a unitary body having the heating elements and cooling water passageways formed therein. The unitary body includes a flat working surface region upon which articles to be thermally processed are mounted. The electrical heating elements are energized to heat up the unitary body to a desired temperature, including the working surface region thereof. Thereafter cooling water is circulated through the cooling water passageways to cool the unitary body, including the working surface region.
Such apparatus also include a temperature sensing device, such as a thermocouple, which sends electrical signals to a control unit indicating the temperature characteristics of the apparatus. Thereby, the control unit regulates the amount of power to the heating elements and the rate of cooling water flow, responsive to the electrical signals, to effect a predetermined thermal cycle or process.
Upon completion of the cooling cycle, the articles mounted to the working surface, which have already undergone the desired thermal processing, can then be removed and additional articles thereafter mounted on the working surface for subsequent thermal processing operations. With such apparatus, it is necessary to wait until the completion of the cooling cycle to remove thermally processed articles from the working surface of the apparatus and mount subsequent article for thermal processing. Since accurate positioning of articles on the working surface is often desired, which requires considerable time, there is a large downtime for such apparatus during the article loading period. It is desirable to provide such an apparatus which does not require waiting until the completion of the cooling cycle prior to loading subsequent articles on the working surface.
Additionally, it is often necessary to accomplish further processing objectives to the articles following the aforementioned thermal processing, wherein precise, repeatable location of parts in relation to one another is required from one process to the next. It is therefore desirable to provide a working surface region having means for maintaining articles in a precise position thereon during the aforementioned thermal processing, while providing for this precise positioning to be maintained during subsequent processing operations. This would provide considerable time savings in not having to accurately position the articles for each processing objective.